Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• smoothly to the dihydroberberine in the absence of the copper salt [37]. This suggests the Cu2+ may be involved in aiding in the air-oxidation to the fully aromatic berberine core. The prime benefit of the route shown in Scheme 1 is the ease of introducing structural variability, as the precursor is easily

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• (I) complexes are frequently used to prepare NHC complexes of late transition metals [37]. As mentioned earlier, Diez-González et al. prepared some NHC–Cu(I) complexes, such as 69 through transmetallation by reacting [(SIPr)AgCl] 68 with the corresponding copper salt at rt (Scheme 23). However

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• - or 3-bromoanisole were also reported) with bromotetradecane in the presence of a copper salt (Figure 10). Then, the deprotection of the phenol function with BBr3 produced 10.2. The deprotonation of the phenol function with NaH in DMF and its reaction with solketal mesylate produced, after the

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• product 172 releasing a Rh(I) species. The Rh(III) species is regenerated in the presence of the copper salt. In another case of C3-(hetero)arylation, Yu and group [104] using palladium for C–H activation of pyridine with phenanthroline as a ligand developed a method in 2016 (Scheme 34). The authors

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• AlMe3 to 4,4-dimethyl-2,5-cyclohexadienone in the presence of a copper salt/chiral ligand and silylating reagent [37][38]. The racemic conjugate addition of nucleophiles to 5 was first investigated, starting with the Gilman reagent which was used in Takemoto and Iwata study (Scheme 6). In addition, a

Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

• Marco Manenti,
• Leonardo Lo Presti,
• Giorgio Molteni and
• Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

• most effectively, further promoting the conversion of the substrate. Other changes in reaction conditions, such as heating at 70 °C, increasing the amount of copper catalyst to 10 mol % and switching the copper salt from CuSO4 to the more soluble Cu(OTf)2, did not improve the yield significantly (Table

• ketimine did not take place. Also conducting the reaction in the absence of B2pin2 (Table 1, entry 14) or copper salt (Table 1, entry 15), respectively, no reaction could be observed and the substrate was recovered together with small amounts of the 1-methylisatin precursor. From the reaction run under the

Electrocatalytic C(sp³)–H/C(sp)–H cross-coupling in continuous flow through TEMPO/copper relay catalysis

• Bin Guo and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2021, 17, 2650–2656, doi:10.3762/bjoc.17.178

• (Table 1, entry 3) and TFE (Table 1, entry 4), albeit in low yields, the reaction failed completely without the copper salt (Table 1, entry 5). Other variations also resulted in diminished yield of 3, such as lowering the loading of Cu(OTf)2 to 5 mol % (Table 1, entry 6), replacing Cu(OTf)2 with other

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• [Cu(dap)2Cl] and visible light are necessary for this transformation. In 2013, Ollivier and co-workers [45] successfully applied the same strategy to the allylation of diphenyliodonium 2. In 2017, Liu’s group [46] reported the copper salt-catalyzed cyclization of vinyl azides 3 with ammonium

• -catalyzed coupling reactions of terminal alkynes was published by Hwang and co-worker. In 2012, they [65] achieved a photoinitiated Sonogashira reaction using aryl halides (bromides and iodides) 20 and aryl- or alkylacetylenes 19. In control experiments, the replacement of the copper salt with palladium

• salts or the substitution of thermal heating for LED irradiation resulted in a low yield of the cross-coupling products 22 and 23, indicating the necessity of the copper salt and LED irradiation. Mild conditions, such as Pd-free and high reaction yields at room temperature, make this method a very

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• adjustments from the previous conditions (Scheme 2) [25], such as conducting the reaction at a higher temperature and adding a copper salt to reoxidize possible Pd(0) species produced in the cyclization process [32]. Two compounds containing quaternary centers were synthetized in moderate yields (Scheme 4

• radical initiator and a copper salt as an additive, the reaction between unactivated olefins and alkanes (in large excess, 50 mL/mmol) afforded anti-Markovnikov hydroalkylation products at high temperature (110 °C) (Scheme 37). Two examples of the synthesis of quaternary carbon centers were reported using

Catalytic trifluoromethylation of iodoarenes by use of 2-trifluoromethylated benzimidazoline as trifluoromethylating reagent

• Tatsuhiro Uchikura,
• Nanami Kamiyama,
• Taisuke Ishikawa and
• Takahiko Akiyama

Beilstein J. Org. Chem. 2020, 16, 2442–2447, doi:10.3762/bjoc.16.198

• recently reported the trifluoromethylation of iodoarenes by use of 2-aryl-2-trifluoromethylbenzimidazoline as the trifluoromethylating reagent in the presence of 3 equiv of a copper salt [22]. The benzimidazoline derivatives could be readily prepared from relatively cheap materials, namely

Chan–Evans–Lam N1-(het)arylation and N1-alkеnylation of 4-fluoroalkylpyrimidin-2(1H)-ones

• Viktor M. Tkachuk,
• Oleh O. Lukianov,
• Mykhailo V. Vovk,
• Isabelle Gillaizeau and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2020, 16, 2304–2313, doi:10.3762/bjoc.16.191

• time to 8 h did not reduce the yield, which remained essentially the same, about 90% (Table 1, entry 18). Heating the reaction mixture also allowed the copper salt and pyridine to be used in substantially lower (catalytic) amounts, though sacrificing the yield to some extent (79%, Table 1, entry 19

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• copper salt, acting as both, the catalyst for C–H activation and the oxidizing agent, was also required. The reaction occurred at higher temperatures (60 °C) compared to other dual catalytic systems. A wide variety of benzamide substrates bearing different functional groups such as alkyl, phenyl, halogen

• single electron-transfer process (Figure 36). In the first place, a bidentate chelated species is formed by the coordination of 1-naphthylamine derivatives with copper salt. The subsequent oxidation of this intermediate with potassium persulfate produces a Cu(III) species, furnishing a radical cation on

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• . After completion of the reaction, water was added to the mixture until precipitation appeared. The precipitate was collected by filtration and washed with plenty of water to remove excess CuCl2, NH4OAc, and reduced copper salt. Compound Q1 (1.4 g, 78%) was obtained as yellowish crystals. 1H NMR (400 MHz

Copper-based fluorinated reagents for the synthesis of CF₂R-containing molecules (R ≠ F)

• Louise Ruyet and
• Tatiana Besset

Beilstein J. Org. Chem. 2020, 16, 1051–1065, doi:10.3762/bjoc.16.92

• ][53][54]. The active species was prepared from TMSCF2PO(OEt)2, a copper salt and an activator. Note that the TMSCF2PO(OEt)2 was easily prepared from the commercially available BrCF2PO(OEt)2 and TMSCl under basic conditions [49]. The access to CF2PO(OEt)2-containing arenes was obtained after a

• co-workers also reported the reaction of the CuCF2PO(OEt)2 reagent with α-diazocarbonyl derivatives. Depending on the copper salt used for the generation of the copper reagent, the reaction with α-diazocarbonyl derivatives provided either the α-fluorovinylphosphonate, in a stereoselective fashion, or

Copper-catalysed alkylation of heterocyclic acceptors with organometallic reagents

• Yafei Guo and
• Syuzanna R. Harutyunyan

Beilstein J. Org. Chem. 2020, 16, 1006–1021, doi:10.3762/bjoc.16.90

• copper-catalysed asymmetric conjugate addition (ACA) of dialkylzinc reagents to N-substituted 2,3-dehydro-4-piperidones 1 in order to access useful chiral piperidine derivatives (Scheme 1A) [15]. They found the catalytic system based on the chiral phosphoramidite L1 and a copper salt to be the most

• the total synthesis of the natural product (+)-myrtine with 14% overall yield (Scheme 1B) [17]. For this application, the highest yield (73%) and enantioselectivity (96% ee) were obtained using the chiral ligand L3 and a copper salt as the catalyst. Despite the fact that examples of high yield and

• acceptors with trialkylaluminium reagents was explored by the group of Alexakis in 2009 (Scheme 11) [41]. Various chiral phosphoramidite ligands, in combination with a copper salt, were found to be efficient catalysts for this transformation, with the best results obtained with the ligand L16. Feringa and

Copper catalysis with redox-active ligands

• Agnideep Das,
• Yufeng Ren,
• Cheriehan Hessin and
• Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

• species is the catalyst resting state and is accessed starting from a dinuclear side-on peroxodicopper(II) intermediate, thus closely mimicking copper tyrosinases [22][23]. Interestingly, further studies have focused on a closely related combination of copper salt, diamine (DBED: N,N’-di-tert

Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons

• Goki Hirata,
• Yu Yamane,
• Naoya Tsubaki,
• Reina Hara and
• Takashi Nishikata

Beilstein J. Org. Chem. 2020, 16, 502–508, doi:10.3762/bjoc.16.45

• reaction of compound 4 if it did not possess an alkyl substituent on the nitrogen atom of the amide bond. Conclusion In summary, we have developed two types of tandem reactions catalyzed by a copper salt. The reaction of 2-bromocarbonyl compounds and aryl-substituted alkynes underwent alkyl radical

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

• Qiao Lin,
• Shiling Zhang and
• Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

• in CH3CN at 100 °C for 16 h, and a full conversion to the 2-aminoethyl acetate product 3a was obtained (Table 1, entry 1). By changing the copper salt to CuBr or CuI, similar results were detected under the same conditions (Table 1, entries 2 and 3). Surprisingly, when this reaction was performed

• without copper salts and decreasing the temperature to 50 °C in CH3CN, still a 99% GC yield of the desired product 3a was obtained (Table 1, entries 4 and 5). These results revealed that the copper salt is not necessary for this ring-opening N-alkylation reaction to take place. Next we evaluated several

Copper-promoted/copper-catalyzed trifluoromethylselenolation reactions

• Clément Ghiazza and
• Anis Tlili

Beilstein J. Org. Chem. 2020, 16, 305–316, doi:10.3762/bjoc.16.30

• , the use discrete copper–SeCF3 complexes allows the trifluoromethylselenolation of a large panel of starting materials. Therein, the main drawback is the generation of a stoichiometric amount of a copper salt as a byproduct of the reaction. On the other hand, Me4NSeCF3 is a very attractive reagent that

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• any copper salt as cocatalyst, complete formation of 3a was also detected after 3 h revealing that copper can be eliminated from the system without any decrease in the system’s efficiency. The source of palladium could also have a significant effect on the reaction’s performance [23]. It was found

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• -selective fluorination of α-bromocarbonyl compounds using a copper/CsF catalyst system (Scheme 32). Tertiary alkyl fluorides could be generated by this fluorination through the assistance of an amide group. From the results, the catalytic cycle of this reaction includes: 1) copper salt induced generation of

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• heterogeneously catalyzed synthesis of imidazo[1,2-a]pyridines from 3 and ketones 20 has been reported (Scheme 7) [101]. Titania-supported CuCl2 (CuCl2/nano TiO2) played the role of catalyst in this transformation under aerobic conditions. Titania support helped in recyclability of the copper salt to four

• that the presence of copper salt is mandatory for the formation of the fused heterocycle as its absence resulted in the formation of the enaminone only. The imines 118, generated in situ via the loss of nitrogen from azide derivatives, were found to be reactive towards 1,3-dipoles 117 to form diverse

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

• Camila S. Pires,
• Daniela H. de Oliveira,
• Maria R. B. Pontel,
• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Diego Alves,
• Raquel G. Jacob and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2018, 14, 2789–2798, doi:10.3762/bjoc.14.256

• copper salt. To confirm the structure of 6, its molecular structure was also analyzed by single-crystal X-ray diffraction (CCDC: 1853770). The molecular structure is demonstrated in Figure 1. Conclusion A variety of 4-(arylselanyl)-1H-pyrazol-5-amines was prepared in a one-pot multicomponent procedure

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• necessary. This means that a dinuclear copper complex – most probably copper(I) acetylide bearing the π-bound copper salt – plays a key role during the cycloaddition step. On the basis of a crossover experiment with an isotopically enriched 63Cu(I) salt it was concluded that the CuAAC involves addition of

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

• Kohsuke Aikawa,
• Kohei Yabuuchi,
• Kota Torii and
• Koichi Mikami

Beilstein J. Org. Chem. 2018, 14, 576–582, doi:10.3762/bjoc.14.44

• , CF2Br, and n-CnF2n+1 (n = 2, 3, 8) groups. Results and Discussion Our initial investigation was focused on the methylation of ethyl trifluoropyruvate (1a) with Me2Zn in the presence of a copper salt bearing a chiral bidentate phosphine ligand (Table 1). We were delighted to find that the reaction

• contrast, the chiral product was obtained in 64% yield in the absence of a copper salt but in low enantioselectivity (Table 2, entry 3). Therefore, decreasing the amount of phosphine ligand (2.4 mol %) to less than that of copper salt led to an enhancement of the enantioselectivity to 70% ee (Table 2